Omron SYSDRIVE RX Series User Manual page 269

CRC-16 Calculation Example
CRC-16
calculation
*1
CRC = FFFFh
Target data
All target data
completed
Interchange the Hi and Lo
bytes of CRC
Completed
<Header and Trailer (Silent Interval)>
•Wait time from receiving the query from the master to the response by the Inverter.
•Be sure to provide 3.5 characters (24 bits) as the wait time. If the length does not reach 3.5
characters, the Inverter does not respond.
•The actual communication wait time is the total of the silent interval (3.5-character length) and
C078 (communication wait time) setting.
Message Configuration: Response
<Total Communication Time>
•The time from receiving query to the response by the Inverter is the total of the silent interval (3.5-
character length) and C078 (communication wait time) setting.
•If sending another query to the Inverter after receiving the response, be sure to provide the silent
interval length (3.5 characters) at the minimum.
<Normal Response>
•If the query is the loop-back function code (08h), the Inverter sends back a response of the same
content as the query.
•If the query is the function code to be written into the holding register or coil (05h, 06h, 0Fh, 10h),
the Inverter sends back the query as it is in response.
•If the query is the function code to be read from the holding register or coil (01h, 03h), the Inverter
makes the slave address and function code the same as the query and attaches the read data to
the query.
*1
CRC
Hi
CRC register (2 bytes)
Exists
*1 *1
CRC = CRC XOR target data
8-bit shift
*1
Shift CRC = CRC
the right
*1
0
Overflow bit
after shift
*1 *1
CRC = CRC
Shift by 1 byte against target data
4-4 Communication Function
Lo
Completed
Bits left
*1
by 1 bit to
1
XOR A001h
4
4-160